Proliferative capacity of cell cultures derived from the human placenta.

The placenta consists largely of fetal tissue, yet at term it displays histological signs of deterioration not apparent in the fetus. To determine whether the apparent degeneration of the placenta is genetically determined, the life-spans of placental cell cultures and the proportion of placental cells capable of incorporating [3H]thymidine for replicative DNA synthesis in vitro were measured. Under the culture conditions employed, the placental cells were removed from the influence of many extrinsic factors thought to play a role in the degeneration of the placenta in vivo. Cultures of fibroblast-like cells derived from the placenta exhibited a reduced life-span and correspondingly reduced proportion of cells able to incorporate [3H]thymidine for DNA synthesis in comparison to cultures derived from the fetal skin and the maternal decidua. These results suggest that intrinsic cellular processes may be involved in the apparent degeneration of the placenta.